1. Field of the Invention
The present invention pertains generally to the field of surgical methods for use of apparatus in-opening an anatomic space with the option of sizing and/or further expanding the dissected space. More particularly, the present invention pertains to surgical methods of dissection, sizing and expansion wherein a balloon device combines the functions of dissection, sizing, and, optionally tissue expansion.
2. Description of the Related Art
In the past, inflatable devices have been utilized to dissect tissue layers to create an anatomic working space to facilitate the performance of laparoscopic or other minimally invasive surgical procedures. For example, in U.S. Pat. No. 5,163,949, to Bonutti, the disclosure of which is hereby incorporated by reference in its entirety, various inflatable devices are disclosed which can be utilized to dissect tissue and create an anatomic working space. A surgical balloon dissector and method of use is also disclosed in U.S. Pat. No. 5,496,345, to Kieturakis et al., the disclosure of which is also hereby incorporated by reference in its entirety. It has been found that a tissue pocket formed by balloon dissection may be more regular and precise than with manual dissection. In contrast to traditional blunt dissection techniques, the dissection balloon creates the tissue pocket while respecting natural tissue planes or boundaries in the anatomy.
A second type of inflatable device, known as a tissue expander, has been utilized as temporary implants to gradually expand a previously dissected pocket over time as the overlying skin and tissue gradually alters (through new cell formation) and expands in response to the force of the tissue expander. In the tissue expander art, it is known that excessive inflation pressures in the expander can cause the undesirable result of tissue necrosis and hence the inflation pressure of the tissue expander must be precisely regulated to avoid necrosis. Because the pressure must be held beneath this pressure level, it is necessary for tissue expanders to be left in place over a prolonged period of time to allow the cutaneous tissues to gradually alter and expand. This requires precise monitoring and periodic adjustment of the expander pressure as the tissue gradually expands over time.
In certain surgical procedures, especially in plastic surgery procedures, it is necessary to dissect a tissue pocket for the later implantation of a prosthetic device. For example, breast augmentation and reconstruction procedures involve dissecting a space or pocket in the breast, sizing the space to assess later appearance and, if necessary, providing tissue expansion in order to achieve the desired aesthetic appearance. The purpose of the sizer is to provide the physician with a visual check or confirmation of the likely final appearance of the breast after the implantation is complete. Previously, two or more different devices have been required to perform the dissection, sizing and expanding steps.
Typically, the breast pocket is manually dissected through the use of a blunt instrument or the surgeons finger. A sizer may then be inserted into the manually dissected space to assess the appearance. If necessary, further manual dissection or tissue expanders are then used to adjust the pocket.
In Johnson et al., U.S. Pat. No. 5,258,026, a surgical procedure for breast augmentation is disclosed, whereby an incision is made in the umbilicus and an elongate hollow tube is introduced into the incision and pushed along the chest wall to form a tunnel to a position behind the breast. The prosthesis is then pushed into the tunnel toward its position behind the breast. In Johnson, the prosthesis itself is utilized as a tissue dissector by overinflating it to 150% of its anticipated ultimate fill volume to create the breast pocket. The prosthesis is then reduced in volume to its intended final volume and left in place. The umbilical incision is then closed and the surgery completed. While Johnson discloses the use of an inflatable member to create a tissue pocket in the breast for the purpose of augmentation, Johnson uses the implant itself to dissect and does not provide a device or method for arbitrarily sizing the tissue pocket after it is dissected or for further expanding the tissue pocket should the size of the initially dissected space be insufficient. In addition, prosthesis manufacturers do not wish their implants to be overinflated as Johnson describes because it may compromise the implant's integrity.
Accordingly, there is a need for improved methods of surgical dissection, sizing and expansion to overcome the aforementioned disadvantages in the prior art.